🧂 How much salt water can hold: the whole packet

🧂 How much salt water can hold · 5th–8th grade · 1 day of testing · free · 60 minutes a sitting

My days, if the fair is 14 days away

Count back from your fair day and write in each date. Fewer days than this? The jobs share days, in this order; nothing is skipped.

Dates from my teacher

• My question is due
• Testing starts
• My results table and graph are due
• My board is due

In this packet

1. 🗓️ My project plan
2. 💭 My hypothesis
3. 🧺 Change, measure, keep the same
4. 🪜 My steps
5. 📊 My results
6. 📓 My logbook
7. ✅ My conclusion
8. ✂️ Board titles to cut out
9. 🏅 The judge's questions and my certificate

If I change how warm the water is, then how many teaspoons of salt dissolve in the water will ________________, because _____________________________________________

What I think will happen, in my own words:

3 levels × 3 tries at each = 9 tries in all. If anything you keep the same changes, you won't know which change made the difference.

What I need

• 🧂 Salt: about a cup
• 🧊 Cold water from the fridge
• 🚰 Water from the tap: left out for an hour, for room temperature
• 🚰 Warm water: warm from the tap, never hot
• 🥛 Clear plastic cups, all the same size: 3
• 🥛 A measuring cup
• 🥄 Measuring spoons
• 🥄 A spoon
• 🌡️ A thermometer (digital, or the red-liquid kind)
• ⏱️ A stopwatch or a kitchen timer

Be safe: 💧 Water

1. Pour a quarter cup each of cold, room-temperature and warm tap water into three clear cups.
2. Read each cup's temperature with the thermometer and write it down.
3. Stir half a teaspoon of salt into the cold cup for 30 seconds. Never drink the salty water.
4. If all the salt is gone, add another half teaspoon and stir again.
5. Stop when some salt is still on the bottom after one minute of stirring.
6. Count the teaspoons that dissolved. Leave out the last half teaspoon, the one that stayed.
7. Do the same with the room-temperature cup and the warm cup, stirring the same way.
8. Pour out, rinse the cups, and do the whole test two more times with fresh water.
9. Find the mean for each temperature, and draw a bar graph.

Write each number in your results table the moment you measure it.

I changed: Water   I measured: how many teaspoons of salt dissolve in the water (teaspoons)

MY GRAPH (a bar graph: water along the bottom, teaspoons up the side)

What I noticed: ______________________________________________

Write something every day you work on it, even the days you only gather things. More days? The three-page logbook prints from peabody.kids/science-fair/templates/logbook.

My hypothesis was ☐ right ☐ partly right ☐ not right.

I know because my numbers show:

What surprised me, or what might have gone wrong (7th and up):

Next time I would test:

Idea: Change a second thing: repeat the test with sugar, and graph salt and sugar side by side at each temperature.

1. What made you want to ask this question? Say something like: I wanted to know: does warm water hold more salt than cold?
2. What did you think would happen, and why? Say something like: I thought changing how warm the water is would change how many teaspoons of salt dissolve in the water, and I wrote down why.
3. What did you change, and what did you measure? Say something like: I changed how warm the water is (Cold from the fridge, Room temperature, Warm from the tap) and measured how many teaspoons of salt dissolve in the water in teaspoons.
4. What did you keep the same, and why does that matter? Say something like: I kept a quarter cup of water in every cup and salt added half a teaspoon at a time the same, so only how warm the water is was different.
5. How many times did you test it? Say something like: 3 times at each of my 3 levels, and I found the middle number.
6. What did you find out? Show me in your numbers. Say something like: Look at my table: Cold from the fridge and Warm from the tap gave different numbers, and here's the pattern.
7. Was your hypothesis right? How do you know? Say something like: My numbers show whether I was right, partly right or not, and I can show you where.
8. Did anything go wrong, or surprise you? Say something like: One try was odd, so I did it again and wrote it in my logbook.
9. If you did it again, what would you change or test next? Say something like: I'd change a second thing: repeat the test with sugar, and graph salt and sugar side by side at each temperature.